Where can i read up on how the body form this somewhat of a symetry during locomotion betwen opposing body parts? Is it some sort of inertia or actually a balancing pose? can this motor pattern be explained matheamthically, in estimation perhaps, especially since the pelvis, shoulder blade and ribcage, spines and muscles, all too follows the same symetry in turns... how do you describe this biomechanical phenomenon in math and physics?